


Dennis Puts the I in Incest

by SoundandColor



Category: It's Always Sunny in Philadelphia
Genre: 1990s, F/M, Prom, Sibling Incest, Sibling Rivalry, Underage Drinking
Language: English
Status: Completed
Published: 2012-03-27
Updated: 2012-03-27
Packaged: 2017-11-02 14:40:56
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,679
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/370113
Author URL: https://archiveofourown.org/users/SoundandColor/pseuds/SoundandColor
Summary: <blockquote class="userstuff">
              <p>He’s going to do something horrible. He’s going to get away with it.</p>
            </blockquote>





	Dennis Puts the I in Incest

**Author's Note:**

  * For [tearupthesky](https://archiveofourown.org/users/tearupthesky/gifts).



> Funny Story, I actually started writing this as a treat for you during Yuletide but I got caught up in my other fics and never got it done. Then, during Porn Battle, I was trolling the prompt post, came upon a familiar request (Dee/Dennis, Prom, Accident) and saw it was you again. I fished this out and finished it up but then I couldn't find a beta and school got crazy so this was, once again, pushed to the back burner. When someone finally agreed to look it over (thanks [pie_is_good](http://pie-is-good.livejournal.com/)!) I sent it off and two months after making her corrections and adding almost a thousand more words (please forgive any errors!) here it is. 
> 
> Oh and, by the by, I tried to write it from Dee's POV but it wasn't happening. All I could hear whenever I opened Word was Dennis' voice whispering from the back of my mind and that scares me more than anything I've ever known...
> 
> I HOPE YOU ENJOY!!!!

**9:13**

**On A Friday**

**Philadelphia, PA**

 

The first step of Dennis’ weekly ritual is to strip.

 

He does it in front of the full-length mirror behind his bedroom door. He does it _slowly_.

 

Removes each item of clothing (t-shirt, jeans, underwear, socks and shoes) and carefully sets them aside as he watches his body being revealed with sloe eyes.

Dennis admires the play of light across sculpted abdomen, toned buttocks high and proud, sensually rounded mouth set into a perfectly symmetrical face. He isn’t too humble to admit he’s hot shit and deserves every one of the many names he’s known by (Mr. Flex. The Body. St. Joe’s Teen Dream. The Golden God), but he’ll only allow himself to be Dennis Reynolds here. 

 

With his dad puttering around downstairs and Dee and his mom still out shopping, he relaxes and gets to work. Dennis pulls out his grandma’s full-length mink—The one he took from his mom’s chest and keeps hidden in the furthest corner of his closet—and lays it across the coverlet on his bed. He straightens it out, imagines the feel of the fur against his naked body.

 

His hands start shaking, but he ignores them for now. Readying himself, setting the scene, waiting for the right moment.

 

This is the best part. He won’t rush through it.

 

He tucks in his sheets and blanket before getting into place in the center of the bed and staring up at the popcorn ceiling. He doesn’t touch himself, not immediately; he goes over the events of the day instead. The suit he chose for prom, the color of his date’s dress and how his choice of corsage will play off it beautifully.

 

He knows the night will be perfect.

 

Not even Dee, the goddamn tard, will be able to destroy it. Not when he handpicked a date for her and chose the dress she’ll wear. He can see the page he tore out of Seventeen Magazine two weeks ago like it was yesterday. A beautiful, baby blue, strapless mermaid gown with a satin finish and rhinestones along the hem. The model had been, of course, ten times more beautiful than his sister, but he figured her back brace wouldn’t ruin the cut of it too much. 

 

He’d taken care of everything. Ordered the limo, brought their tickets, and with Dee and his mom out to pick up the gown he ordered, everything was on track for an unforgettable night.

 

Now it was time for Dennis to take care of himself.

 

His hands have already made their way to his abdomen by the time he allows himself to consider any anatomy below the waist, and he palms the skin there thoughtfully, subconsciously deciding to add 75 more crunches to his morning workout for the small pouch he thinks might be growing there.

 

He runs his teeth along his bottom lip and lets his head fall to the side as he finally takes himself in hand. He’s mostly hard already, and it would be easy to end this quickly. Four or five quick pulls and he could be asleep in minutes, and on any other day, that’s exactly what he’d do. However, today is special. He reaches into the middle drawer of his nightstand and pulls out some baby oil. Squeezes some into his hand and follows a familiar path to a well-loved destination.

 

He catches his own gaze in the mirror above his bureau, lets his hand glide along the taught skin of his shaft and tightly grips the head. The firmness of his grasp hurts, just a bit, and the first circuit makes him gasp. By the third, he’s got his feet planted firmly on the mattress and is worried he won’t last much longer.

 

That’s when he hears the front door open and loud, feminine voices fill the house. Dee and his mother always end every outing the same.  He tries to ignore them and slows his stroke. Stops and squeezes the sensitive crown but everything’s wrong now. They’ve knocked him out of his zone and he’s considering just getting this over with and going to bed when he decides against it. Dennis is always helping other people, _always_ , and he won’t let them take this away from him.

 

He starts off trying to pretend they aren’t downstairs but when he thinks about it, their argument is actually seems to be helping him hold off longer.  He focuses on it.

 

They’re yelling about something he can only catch snatches of.

 

(“…looks like a creature from the lagoon… children will cry… they can’t be blamed, Deandra.”

 

“Why won’t you…my dress?”

 

“…Prior engagements…”)

 

His mother says something he can’t hear and Dee lets out an animal sound of rage before stomping up the stairs and slamming her door.

 

At first, he only hears her moving things moved around in there—drawers opening and closing, what he thinks is the closet door being flung wide—as Dee mutters to herself like a crazy person and pretty much confirms every bad thought he’s ever had about her. Then she goes quiet and just when he decides she's settled down, Dennis hears soft sounds coming through the wall between their rooms. Little moans and whines he can’t place and isn’t really capable of paying attention to because his dick’s too hard now to think of anything else. But she’s still there, a constant thrum just beneath the surface of his thoughts.

 

He stares at himself in the mirror, takes deep breathes, works his thumb along the fat vein running the length of his cock and he’s so strung tight that his thighs are shaking with wanting to finish.

 

Dee makes a little gasping noise then that he won’t remember hearing later and somewhere in his subconscious, he realizes… ( _she_ ’s _crying_ )

 

Dennis’ mouth falls open when he finally comes, but he doesn’t make a sound.

 

—

 

After his shower, he climbs back into bed, cuddles up with his pillow and sleeps like a baby.

 

—

 

**5:45**

**On A Saturday**

**Philadeplia, PA**

********

On the big day, neither of their parents bothers showing up.

 

Their dad’s probably drunk somewhere and he couldn’t even guess where their mom’s gone. He expects Dee to whine over it, to throw a fit about them ruining everything but when she knocks on his door, the only thing she says when he opens it is, “Zip me.”

 

He just stares at first. Instead of the beautiful dress he picked, she’s in some horrible monstrosity with magenta tulle and a silhouette that hadn’t even been fashionable two seasons ago. Dennis is completely dumb struck by her audacity. “This isn’t what you’re wearing.”

 

“Yes it is.”

 

“But this isn’t the dress I picked out.”

 

“Yeah,” she says slowly, as if _he’s_ the idiot in this situation. “It’s the one _I_ picked out.”

 

“Deandra…” it takes him a moment to find the correct words. "That dress..."

 

"Is unique!"

 

"Close. Looks like shit would be closer."

 

"Whatever, Boner, if you like the other one so much, you should show up in it. I don’t think anyone would be surprised if you did.”

 

Dennis scoffs, anxious about whether that could be true before deciding it definitely isn't. “Well, we both know that wouldn't happen.”

 

“If you say so.”

 

This is about the time he slams the door in her face.

 

—

 

They’re standing outside the front door, two beers in, when the limo finally shows up. Dennis raises his bottle, and Dee mimics his pose.

 

“To a momentous night!”

 

“Smash ‘em up?”

 

“Smash ‘em up!”          

 

“They don’t bother sweeping away the shards of glass before leaving the house. They’ll worry about it later.

 

—

 

“The hell, Dennis! “

 

His date’s got a beer in one hand and the top button of his pants in the other so Dee’s sudden presence on their side of the limo isn’t exactly welcome. Especially since she’s bitching about something or other.

 

“What’re you going on about now?” He asks, distractedly.

 

“This is the _amazing friend_ you just had to set me up with. The one who would _make my prom magical_.”

 

“Sure,” he glances at Charlie and Mac, one passed out with a paper bag of paint in his lap and the other counting colorful pills out of a zip lock bag. “You’ve got your pick of the litter, and I bet Mac’s got something on him that could help you—“

 

“Shut up! Shut up! Shut up!” she growls, before crossing her arms and staring out the window.

 

“— _relax_! Jeez, Dee! I’m trying to help you out here. “ He mutters, frowning at his sister’s profile and thinking of how ungrateful she is, as his date begins to unzip him.

 

—

 

Dee, Charlie and Mac disappear as soon as they step inside St. Joes but Dennis doesn't miss them. He's searching for a strategic point against the wall; somewhere he can lean and be seen without looking like he’s trying too hard. He’s so absorbed in the hunt he doesn’t notice his date trying to get his attention until she’s practically on top of him.

 

“You and me in the janitor’s closet. Be there in 20 minutes.” She tries to whisper it in his ear, but the music’s too loud, and after he’s asked her to repeat herself 3 times, she just sort of yells it wetly against his cheek. This close, she smells like throw up and rum and it’s kinda gross, but he really wants to get laid so he ignores it.

 

He decides to show up in 30—Dennis stands in the boys restroom for 15 of those minutes, he's always likes to make an entrance when possible—with the condom already on instead. They both know what they’re here for and he still has to make sure he's seen by the right people. There’s no need to waste any more time with her than necessary.

 

He pokes his head out into the hall, makes sure none of the teachers are there before stepping out and moving toward the closet quickly. He unbuttons his jacket along the way, pops open the top three buttons on his shirt and musses his hair to add to his already debonair look, cracks his knuckles once, whispers, “It’s go time,” to himself as he opens the door and closes it behind himself.

 

Things are off right from the beginning. She hasn’t turned on the light like she normally does and the room is dark as he walks a little further in. His eyes have only just begun to adjust when he notices someone standing off to the side. Dennis is barely able to contain a small shriek of surprise but he ignores it. Licks his lips as he steps closer.

 

Even though this is where they agreed to meet and the room is too dark to really tell, the girl in front of him isn’t his date. The closer he gets, the more sure of it he is. She’s too tall, her dress is already pressing against the front of his pants when it should’ve been more fitted, her perfume is sweet and sugary rather than the more earthy scent she’d spritzed on when they got out of the limo, but even though the presence isn’t _right_ , it’s still _familiar_. He’s too curious to walk away and why should he? A little stranger danger never hurt anyone.

 

He still doesn’t move nearer though, forcing her to close the distance left between them. She reaches out, palms flat to his chest before letting them slip down to his stomach. She hesitates then, pushes against him hard, testing. He guesses her boyfriend isn’t as cut as he is and that’s just another check in Dennis’ column. He waits to see what she’ll do. If she’ll leave, push him away, run screaming…

 

She finishes unbuttoning his shirt.

 

He steps closer then, tries to lean into her but something cool and hard stops him. A sound like alarm bells goes off in the back of his mind, he brushes it aside. Gets down to his knees to get under her dress and she helpfully steps out of her underwear when he pulls them down

 

He looks up at her. They haven’t said anything to one another yet, and it’s really fuckin’ sexy. Like a scene from _Wild Orchid_ or something.  He can’t wait to tell Mac and Charlie. With that thought, he stands abruptly, crowding her back toward a low shelf, and hears a shrieking sound like metal on metal when she bumps into it. That’s when he knows, _he fucking knows_ , and stops short but she doesn’t. Dee pulls herself up and tugs him closer. 

 

This is wrong. Definitely the worst thing he’s ever come close to doing and Dennis has been a party to a lot of awful shit, but if he’s being honest, that’s part of the excitement of it, too. The wrongness. The fact that he can think about doing this thing and no one would know.

 

Dennis lets her pull him in and he grabs the bottom of her dress, pushes it up around her waist, the tulle scratching at his arms and under his chin. He puts his hand on her thigh and tells himself, _I haven’t done anything yet_. _I can stop this whenever I want_. _I won’t let it go any further than this_. Then he steps closer, feels the heat of her against his cock, and he stops lying to himself.

 

He’s going to do it. This is going to happen. He’s going to fuck his sister. Instead of the panic and disgust he should feel, arousal pulses over him. Now that he's made a decision, he's not nervous anymore.

 

He’s going to do something horrible. He’s going to get away with it.

 

Dennis Feels calm.

 

The heel of her shoe scrapes against the back of his thigh as he adjusts her leg around his waist, pulls himself free from his trousers and maneuvers his hips to sink inside of her. Her nails bite against his shoulder as they begin to move against one another. Pushing when they should be pulling, moving too slowly one minute and too quickly the next, working against one another instead of moving together. They can’t find a rhythm.

 

Dennis sighs. He always has to do everything.

 

He grabs the bottom of her brace ( _don’t think. don’t think_.) and uses it as leverage to take control and slide her on and off his dick. She makes a startled sound in the back of her throat, crosses her ankles behind his thighs, and Dennis is torn between gagging and moaning at how wet she’s getting. How hot this is making him.

 

He’s gonna come.  He’s gonna finish, and he’s going to slip out of this room without saying a word to her, she’ll never know, and one day, he’ll forget too. He’ll forget this ever happened, and everything will be normal again. All he has to do is come, then it’ll be over. It has to. It _has_ to.

 

Dennis slips his hand between her thighs and slides his thumb across her clit. She jerks against him, and he jerks back. Impressed with himself. _That’s right_ , he thinks. _That’s right._

 

But this isn’t right. She’s his sister (…his own flesh, his own blood, Sweet Dee… Dennis’ fingers and Dennis’ hips speed up without conscious thought) for god’s sake! There are probably tons of laws against what they’re doing and, almost worse than the whole being related deal, she’s so fifth string.

 

The reputation he’s steadily built up would take a major hit if he were ever caught with a loser like her. The thought is fleeting. He can feel the amazing pressure of orgasm building in his gut, and he doesn’t have the ability to split his attention.

 

His hips move faster and when she gasps, tightening around him, he follows her over. Grabs her hips and pulls her flush to him, pelvis to pelvis, lets his face fall into the curve of her neck and breathes in the mixture of sweat and perfume there.  He wants to lick it, to bite it but the very same part of him that allowed this to happen thinks that’s a step too far. That it’ll open doors to places with even worse things than what they’ve just done hiding behind them.

 

Dennis backs away from her then and takes a breath, trying to think of an exit strategy, when someone starts to turn the knob. “Dee? Are you in there?”

 

They startle further apart and freeze like criminals at the sound. He shoves his dick back in his pants, not bothering to pull the condom off, and by all the rustling directly in front of him, he guesses she’s pulling her clothes back on too.

 

“Is anyone—“

 

It’s Cricket out there and the kid sounds really excited, happier than a slug like him deserves to be, and even though he doesn’t usually bother Dennis so much, hearing his voice now makes Dennis tense. He’s suddenly angry.  So pissed off he could throw the door open, strangle him until his face turns blue and his eyes bug out. Until the fine capillaries in his eyes burst, and his tongue lulls from the corner of his mouth. 

 

Dennis only vaguely realizes that he’s getting hard again.

 

“Get the fuck away from this goddamn door, Cricket!”

 

She jumps like a livewire, he can hear something heavy fall and clatter to the ground. Neither of them moves again.

 

“Oh Dennis! I thought… You haven’t seen your sister have you?”

 

“You think she’s in here with me?”

 

“Of course not!” The certainty in Cricket’s voice soothes him.

 

“Then move the fuck on, plebe!”

 

“Of course. I’m—“ he doesn’t finish his thought, just scampers off.

 

Dennis takes a breath and feels along the wall, flips the light switch on. This is it, his _Just_ _One of the Guys_ titty reveal. A sort of, _all your aluminum monsters come home to roost_ type moment. She heard his voice. She knows who he is, now it’s time for her to see.

 

When he turns around, she doesn’t look disgusted or ashamed or even shocked for that matter. She just looks scared, more than that, terrified. Her mouth is open in a wet O, her eyes glittering with something other than tears. He stares at her, swallowing thickly. She knew; he’s sure of it. Maybe not as long as he did, but she’d figured it out at some point. He suddenly doesn’t know how he feels about this. When it was just him with a secret to keep, Dennis felt in control but now that she knows... he suddenly can’t catch his breath. He thinks of all those doors even he agrees they can’t ever open.

 

“Dee?”

 

“… Yes?"

 

“Him? _Really_?” He can tell that’s not what she expected to hear. It wasn’t exactly what he expected to say either but now that it’s out there, he feels entitled to an answer.

 

“Huh?”

 

“You were in here waiting for _him_!”

 

Her features scrunch up unattractively “—It’s none of your business!”

 

“It is when you’re screwing someone even lower down the rung than yourself. It looks bad, and my name will not be sullied, Deandra!”  He grabs her arm and wags his finger in her face. “My name will not be sullied!”

 

“Oh, get off it, Dennis,” she orders, pulling out of his grasp. “This…" he freezes up for a moment, "whatever it is with Cricket," she clarifies, "isn’t exactly something I want getting out either. Besides, I think you should be more worried about the fact that you smell like afterbirth than whatever I might be doing.”

 

He furtively tries to sniff himself as she struggles off the shelf. “I do not.”

 

“Whatevs, turkey.” she mutters, breathing hard and trying to right the bottom of her dress. Dennis grimaces, turning away and feeling awkward while trying not to think about why.

 

“I’m gonna leave first,” he says without asking what she thinks. “You wait a few, then follow.”

 

“Hey!”

 

“Cricket’s out there somewhere. You want him to see you coming out of here?” That shuts her up quick, and he slips out of the door without a backward glance.

 

—

 

He notices her come back into the cafeteria exactly 23 minutes later. Not that he was waiting or anything. He just wanted to make sure the goddamn idiot didn’t blow their cover. His missing date comes in not long after Dee, spots him and throws her arms around his neck before kissing him. Her mouth tastes like Colgate, and she looks sweatier than usual, flushed and sleepy. He’s suspicious. “Where have you been?”

 

“Where have you been? You never showed up.”

 

"I went where you told me to!"

 

"The closet near the theatre on the third floor?"

 

" _No_ , the one on the second down from the boys restroom. We've never met on the third floor."

 

"But didn't we—" she stops short, eyes narrowed in thought before they go wide. "Yeah, you're right. Sorry."

 

"Then where—" she doesn’t wait for him to finish, just pulls him toward the line for pictures as he follows his sister's movements from the corner of his eye.

 

Charlie’s woken up from his huffing-induced stupor and swarms Dee as soon as she steps out onto the floor. She brushes him off at first rolling her eyes and yelling whenever he gets too close, but he can see her softening. He watches her curiously. Concedes (only in this moment. If you asked him later he’d deny it) that maybe the dress isn’t quite as garish as he’d first thought. That maybe, under the right conditions and dim lighting, she might look almost pretty in it.

 

Then he catches sight of himself reflected in the small mirror the photographer has set up. He begins slicking his hair back into place, righting his tux, practicing a cool yet aloof smile for the picture and by the time his date pulls him in front of the camera, he’s completely forgotten he was thinking of Dee at all.


End file.
